As is known in the art, feed structures are used to couple a radar or communication system to an array of antenna elements.
As is also known, one type of antenna is fabricated as a panel consisting of multiple elements to constitute a phased array. Such panels are typically flat or can be made to conform to curved surfaces. The RF elements in the panel must be synchronized in both frequency and phase to allow for beam steering in both transmit and receive modes. At each antenna element, frequency and phase must be adjustable to provide proper collimated and directed antenna beams. With present technology, a microwave network, known as a beamformer, is used as the feed network. Typically, such beamformers are binary split corporate feeds implemented in multi-layer circuit boards using embedded RF transmission line. The same boards also accommodate surface mounted microchips that further processing RF signals in both transmit and receive modes. For example, an embedded RF transmission feed panel is typically stripline with alternate layers of line and groundplane. As many as 23 layers comprise such a board in one example. Such panels having these layered metallic transmission lines must be very well aligned and must allow for through-vias. They are therefore relatively large in size and weight, as well as costly. Further, microwave losses and unwanted modes within the multilayer board complicate design and manufacture.